Author(s): Wasis Wardoyo; Djoko Legono; Rachmad Jayadi; Teuku Faisal Fathani
Linked Author(s): Djoko Legono
Keywords: Pyroclastic deposit; Sediment concentration; Volcanic rivers; Sediment transport
Abstract: Gendol River is one among 12 rivers that flows from Mt. Merapi. As one of the most active volcanoes in Indonesia, Mt. Merapi erupts frequently, accompanied by large amount of pyroclastic material. Such material will then be transported through the rivers by means of either deep or shallow landslides, due to instability or rainfall triggered phenomenon, and then settle in alluvial fan areas. Further migration of this settled sediment along the river may occur through both natural (hydraulics phenomena) mechanisms as well as anthropogenic (human induced) process. This research studies a partial aspect of natural hydraulics phenomena of the Gendol River, i.e. the pyroclastic deposit characteristics, which then (applying given rainfall characteristics), would be used to study the sediment transport mechanism. Sensitivity analysis on the adopted fluid mixture equation is also carried out as a part of the study on the sediment transport mechanism. Results of the study show that the dynamic of the C*characteristics of pyroclastic deposits of the Gendol River significantly affects the transport mechanism. Such dynamics may become more complex due to the action of continuous and intermittent rainfall events. Further application on the developed model of sediment transport phenomena may lead to a proper management of pyroclastic deposit.